Optical performance monitoring is an important function in an optical communications network. By monitoring and measuring performance of optical components and/or optical signals at some positional points in the optical communications network in real time, an actual status of the optical network is obtained, and network management and maintenance is performed on such a basis. Common performance monitoring of an optical signal includes measurement for a wavelength, a power, an optical signal-to-noise ratio (OSNR) and the like of the optical signal.
In an optical power monitoring solution in the prior art, a power of each wavelength channel in a wavelength division multiplexing (WDM) system is measured, and is reported to a network management system (NMS). However, sometimes some wavelength channels do not have a real service signal, but have relatively high amplified spontaneous emission (ASE) noise and have optical powers close to that of an optical channel with a real service. In the prior art, a power of a channel without a real service signal is still measured, and is reported as a power of an optical signal. However, the optical signal actually does not exist in the system. Therefore, the network management system erroneously considers that the wavelength channel includes a service signal whose optical power is the optical power obtained by means of measurement, which results in incorrect operation and management.